I-square and guide means for drafting

ABSTRACT

A drafting board has elongated recesses along the sides thereof, said recesses having specially formed teeth for interlocking with corresponding teeth on cross members of an I-square. The bottom of the drafting board converts into legs thereby opening up the translucent center portion for conversion to a tracing table. Step spacers for lines are positionable on the I-square and include stepped surfaces for forming multiple parallel lines; a single step spacer being usable with a novel rider rule by cooperation with a guide finger on the same. Fractional notches on the finger provide increased numbers of accurately spaced lines. The rider rule is movable along a 45 degree angle to provide station keeping force during use; a scale on the rider rule and perpendicular thereto providing a quick reference for line spacing. Side guides snap on the I-square and extend beneath the rider rule.

United States Patent Robers, deceased 1 Sept. 5, 1972 [54] l-SQUARE AND GUIDE MEANS FOR 2,394,619 2/1946 Lenz ..33/108 D G FOREIGN PATENTS OR APPLICATIONS [72] Inventor: Murray K. Ruben, deceased, late of Somerset, by May Rogers, 1,090,653 10/1954 France ..33/41 B Emma-ix H V V V 77 V 960,422 3/1957 Germany ..33/108 Assign? Muhujm M Cm Mb 8,635 1895 Great Britain ..33l80 Ferguson 7' Primary Examiner-Harry N. Haroian [22] Filed: Nov. 4, 1969 Attorney-Lowe and King [21] Appl. No.2 873,962 [57] ABSTRACT A drafting board has elongated recesses along the 8| "3348; sides thaw; said recesses having specially famed I I u u n a n I 4 u n a a e s a n a n a l a u a a n 1 o a I u I I n u I a a l 1 n a n [58] FleldotSearch ..33/76,80,81.79, cross members of an l square The bottom of the drafting board converts into legs thereby opening up the translucent center portion for conversion to a trac- [56] New CM ing table. Step spacers for lines are positionable on the UNlTED PATENTS l sclquare anldlirlielude stepgled surfaces for it'perrning mail]- tlpe parale mes; a sm e step spacer mg usa e 3,380,l64 Norlsliedo a novel rider H y cooperation a guide BO y finger on the me. natches on the finger 353; i 2 u 0 provide increased numbers of accurately spaced lines. 3 [1890 Cl 33/81 The rider rule is movable along a 45 degree angle to 579,183 4 [81 X provide station keeping force during use; a scale on I 092'107 3119 J x the rider rule and perpendicular thereto providing a 609 611918 g; n "33/80 x quick reference for line spacing. Side guides snap on 2 089 757 8/1937 Niel/GEEK:11:21:11....33/76 "Squaw and tend the ride 2,100,114 11/1937 Walsh.......................33/l84.5 15 Claims, 27 Drawing figures 2,219,766 10/1940 Cotterman ..33/76 r a: j

Ia um I \l\\ I.

phonemr --u tnr- I .iJ' A J 1 l 7, 1

P'A'TENTEBSEP 51912 SHEU 2 0F 7 PATENTEDsEP 5 Ian 3.688.409 sumsur'! wvmroz,

arc af A 770/? EYS KTENTEUstr 5 m2 SHEU B [If T m E @Q a m/vzwroz, Ame/ark F0656 Mme. F0656,

fxecufr/x fir lrlaflvfrs 1 I-SQUARE AND GUIDE MEANS FOR DRAFTING This invention comprises a novel and useful I-square and guide means for drafting and more particularly pertains to a system including a method and an apparatus which will facilitate the placing of lines whether straight or of other shapes, upon a sheet of material with precision and accuracy in selected, predetermined spaced relation with respect to a base line or guide surface.

It is the principal object of this invention to provide a system, involving both method and apparatus, whereby the draftsman may with precision and rapidity produce lines, whether straight or of various shapes, in predetermined controllably and adjustably varied spaced relations.

An important object is to provide a novel and improved drawing board and I-square having an adjustable interlocking engagement whereby to facilitate the re-engagement of the I-square upon the board in precisely oriented position relative to another predetermined precisely oriented relation of the I-square and board.

Another important aim of the invention is to provide a simple but highly effective interlocking engagement of an l-square and a drawing board such that the square in one manner of connection with the board may be precisely located at predetermined spaced positions of orientation upon the board and in an alternative manner of connection may be precisely located at intermediate spaced positions upon the board.

A further important purpose is to provide an apparatus wherein a guide means may be readily and precisely engaged interlockingly with a drafting board in predetermined selectively spaced positions together with a gauging means cooperating therewith for accurately locating a line at preselected fractional subdivisions of the spacing between said predetermined spaced positions.

An additional important intent of this invention is to provide an improved drafting board in accordance with the foregoing objects which, being of a translucent construction may be readily employed as a tracing board.

A still further important object of this invention is to provide a cooperating interlocking draftsmans board and I-square wherein the I-square is interlockingly engaged at both its ends with opposite sides of the board and wherein the I-square may be moved across the board by successive intervals of predetermined precisely spaced distances through the action of the interlocking means.

A subordinate object of the invention, in accordance with the preceding objects, is to provide an interlocking, selectively adjustable connection for I-square and drawing board wherein the effects of wear in the interlocking connection may be easily and effectively compensated.

Yet another important object of the invention is to provide an apparatus in accordance with the foregoing objects which will readily permit the use of various attachments for obtaining line spacings at selected fractions of the normal line spacing permitted by the interconnecting means.

Still another important object of the invention is to provide an adjustable interlockingly engaged drawing board and l-square construction wherein the opposite ends of the l-square may be each wedgingly and interlockingly engaged with cooperating elements on the drawing board to insure the positioning of the l-square in precisely parallel adjustable spaced positions upon the board.

A still further important object of the invention is to provide a drafting board construction in accordance with the preceding object wherein an interlocking connection between the I-square and a drawing board utilizes a wedging engagement of cooperating toothed surfaces on the board and I-square which will not only positively lock the I-square to the board in selectively adjusted positions thereon but will also afford the secure interlocking engagement even though the engaging surfaces become worn in use.

These together with other objects and advantages which will become subsequently apparent reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout, and in which:

FIG. 1 is a view intop plan of the drawing board and I-square in accordance with a preferred form of the invention, an alternative position of the I-square being shown in dot and dash lines thereon and an Lshaped square employed therewith;

FIG. 2 is a bottom perspective board of FIG. 1;

FIG. 3 is a detailed view taken in vertical section upon an enlarged scale through the I-sq uare and board and substantially upon the plane indicated by the section line 3-3 of FIG. 1, parts being broken away;

FIG. 4 is a detailed view taken in vertical section and at right angles to FIG. 3 upon an enlarged scale through the I-square and board and substantially upon the plane indicated by the section line 4-4 of FIG. 1, parts being broken away;

FIG. 5 is a detailed view in vertical section and upon an enlarged scale substantially upon the plane indicated by section line 5-5 of FIG. 1 and showing the precision locking adjustment of the I-sq uare and board;

FIG. 5A is a detailed view very similar to FIG. 5 but showing the I-square reversed and locked to the board at the other side thereof to effect an adjustment of the view of the drawing T-square upon the board at intermediate positions with respect to the adjustment positions obtained in FIG. 5;

FIG. 6 is a detailed view taken upon an enlarged scale in vertical sections substantially upon the plane indicated by section line 6-6 of FIG. 2 and showing the locking means of the folding supporting legs of the drawing board when the board is employed as a tracing board;

FIG. 7 is a side elevational view of the board in a raised and inclined position upon its supporting legs when employed as a translucent tracing board;

FIG. 8 is a fragmentary view in top plan of the board, I-square, step spacers and a line and border rule employed to effect a precision spacing of the rule for drawing very closely spaced lines at distances which are fractions of those resulting from the use of an interlocking connection between the I-square and board;

FIG. 9 is a detailed view upon an enlarged scale and in vertical section taken substantially upon the plane indicated by section line 9-9 of FIG. 8;

FIG. is a perspective view of the line and border rule of FIG. 8;

FIG. 11 is a perspective view of the step spacer of FIG. 8;

FIG. 12 is a top plan view of a simplified modification of the I-square and drawing board of FIG. 1;

FIG. 13 is a detailed viewin vertical section upon an enlarged scale of the drawing board and I-square taken substantially upon a plane indicated by section line 13-13 of FIG. 12, parts being broken away and an alternative position of the I-square upon the board being shown in dot and dash lines thereon;

FIG. 14 is a detailed view in vertical section and at right angles to FIG. 13 and upon an enlarged scale through the precision locking means of the board and lsquare substantially upon the plane indicated by the section line 14-14 of FIG. 12;

FIGS. 15 and 16 are diagrammatic views illustrating the reversal of the l-square upon the board to obtain intermediate spaced positions of the I-square upon the board;

FIG. 17 is a perspective view of the line spacer in accordance with the invention;

FIG. 18 is a vertical transverse sectional view taken substantially upon the plane indicated by section line 18-18 ofFIG. 17;

FIG. 19 is a vertical longitudinal sectional view taken substantially upon the plane indicated by section line 19-19 of FIG. 17; and

FIGS. 20 and 21 are plan views showing the reversed positioning of the line spacer of FIG. 17 and its use against a straight edge such as that of the l-square in order to obtain lines at full and half spaces from each other;

FIG. 22 is an alternative embodiment of the drafting system shown in FIGS. 8-11 wherein the rule is formed as a rider on the I-square and one step spacer is employed;

FIG. 23 is a perspective view of a clip-on side limit gauge for use with the system of FIG. 22;

FIGS. 24 and 25 are cross sectional views taken along lines 2424 and 25-25, respectively, of FIG. 22; and

FIG. 27 is a schematic operational drawing of the use of the step spacer of FIG. 22.

The present invention relates to a system for enabling a draftsman to position lines upon a sheet in parallel positions at definite predetermined spacings from a reference orientation line and with facility and certainty. It involves both a novel and improved apparatus together with a novel method of operating the apparatus. The apparatus is shown in its preferred form in FIGS. 1-6, while a simplified and modified construction of the apparatus is shown in FIGS. 12-16. FIGS. 8-11, 17-21 and 22-26 disclose various accessories and attachments which may be utilized in either of the two forms of the drafting apparatus.

Referring first to the preferred embodiment of FIGS. 1-6, it will be seen that there is provided a drafting board indicated generally by the numeral 10 which is of a conventional form, together with a guide blade which may be in the form of an T-square and which is indicated generally by the numeral 12.

The drafting board 10 may be either formed as a single unitary piece of material of a plate-like character or it may be built up as a laminated construction as suggested in FIG. 2 of a plurality of plates or plate-like components rigidly assembled together. Preferably the board whether of one-piece or of laminated construction consists of a translucent Lucite or other suitable material to which a sheet of material may be detachably secured as by draftsman's tape or any other suitable manner in a position to permit the drawings of lines thereon.

Upon what may be termed its front or top side, the drafting board has a planar flat surface 14 to receive the sheet of material. Along its edges or marginal portions, this top side is provided with recessed strips or surfaces 16 upon which are provided strip-like toothed surfaces or elements 18 having teeth 20 thereon. These elements 18 comprise parts of the interlocking connection between the blade 12 and the board 10 as set forth hereinafter.

In some instances, the elements 18 may be separately formed and securely attached to the recess surfaces 16. In other instances they may be integral therewith. In either event, it is preferred that the strips 18 shall be so placed that their outer edges are spaced somewhat inwardly from the edge of the drawing board and such that the top surfaces of their teeth 20 are below (see FIG. 5) or coplanar with but in any event do not extend above the plane surface 14 of the board. In this manner, there are no projections above the board surface 14 which will interfere with the sliding movement of the I-square I2 thereover or of the other drafting implements which may be placed thereon.

At the four corners of the board, the strips 18 are discontinuous where they intersect thus exposing a portion of surface 16 thereby defining a recessed area 22. The teeth 20 otherwise are continuous from edge to edge of the board 10. Cleaning pads 26 may be applied to the surface of the guide blade 12 for cleaning drafting pens and like elements, such pads being known as De-Gooping" pads.

Upon its reverse or bottom face, as shown in FIG. 2, the drafting board is provided with a suitably shaped recess 28 therein while outwardly of this recess and between opposite sides of the board there are provided recessed channels or grooves 30 for a purpose to be now described.

A pair of folding leg assemblies are mounted in the recess 28 and serve to support the board in an inclined or tilted position as shown in FIG. 7 so that by provid ing alight source 32 of any suitable character below the board, the light will pass through the translucent board and enable the use of the board as a tracing board in accordance with conventional drafting practice.

The leg assemblies each include a pair of outer plates or panels 34 which are hingedly connected as by pianotype hinge 36 with the edge of the recess 28 which is adjacent to the channel 30. A second plate or panel 38 is disposed in the recess and is in turn connected as by a piano-type hinge 40 with the previously mentioned panels 34. The dimensions of these panels 34 and 38 are such that in their folded position as shown in FIG. 2 they substantially completely fill the recess so that the abutting adjacent edges of the panels 38 may be releasably locked in the folded position by any suitable locking device. For this purpose, the latching construction shown in FIGS. 2 and 6 may be advantageously employed. The wall of the recess 28 is provided with a slot or chamber 42 in which is slidably received a latch or keeper 44 having a pair of depending flanges 46 and 48 comprising fingergrip and stop means for actuating the sliding latch. A keeper plate 50 overlies the platelike sliding latch 44 to retain it slidingly in the recesses 28 and 42. The latch 44 is so disposed that it may be moved into overlapping relationship with the adjacent edge of the two panels 38 and retain them in their folded and stored position in the recess 28. Alternatively, the latch may be pushed back to the recess 42 thus releasing the edges of the panels 38 so that they be opened into the position shown in FIG. 7.

In their open position, as will be more readily apparent from FIG. 7, the unhinged edges of the panels 38 are disposed in the channels or slots 30 to thus securely position the panels to constitute legs for the drafting board.

Referring now especially to FIGS. 5 and 5A, it will be noted that the l-sq uare or guide blade 12 consists of a flat blade 52 which adjacent one end has secured thereto as by fastening screws 54 a cross-bar 56. As shown clearly in FIG. 5, the blade 52 has enlarged bores 58 therethrough which are counterbored at 60 to receive in a countersunk fashion the heads of the fasteners 54. In this manner, the cross member 56 may be from time to time adjusted with respect to its position upon the blade 52 as may be required.

It will be further noted that the pair of longitudinal edges of the top surface of the blade 52 are likewise recessed as at 62 to provide shoulders for a purpose to be subsequently apparent in connection with the step spacer elements shown in FIGS. 8, 9 and 11.

it is an important feature of this invention that the undersurface of the cross members 56 of the I-square shall likewise be provided with a series of teeth 64 which are complementary to and cooperate with the teeth on the strip 18. The arrangement is such that when the tooth surfaces of the members 56 and 18 are engaged as shown in FIG. 5, the wedging action of the appropriately leveled or relatively inclined surfaces of the cooperating teeth will positively preclude any shifting of the l-square upon the board and thus will interlock or maintain the l-square in fixed adjusted position upon the board. Further, the arrangement is such that the top surface 66 of the cross member 56 is coplanar with the top surface 14 of the board so that no obstruction is provided to the sliding of drafting implements across the surface during drafting operation. Such a drafting implement is an L-shaped square 67 illustrated in F l6. 1.

A very important feature of the invention resides in the precise dimensions or spacing between adjacent teeth 20 and of course of the corresponding teeth 64 of the cross member 56. This spacing is preferably at a uniform fixed distance as for example one-half an inch. Consequently, when the l-square is applied upon the board, the teeth on the l-square may be engaged with those of the board to lock the I-square in adjusted position. By then releasing the teeth and moving them into engagement with the next tooth, the l-square will be shifted one-half an inch with certainty and precision. Consequently, the l-square may be removed from and replaced upon the board as often as may be desired and will be instantly aligned with or properly correlated with its preceding position with certainty.

A further important feature of the invention resides in the arrangement of the teeth on the cross member 56 being disposed at a different distance from the opposite side edges of the blade 52 of the l-square. The arrangement is such that preferably the corresponding portion of the teeth on the l-square cross member are positioned at a distance indicated at 70 which is displaced from the edges of the l-square by one-half of the distance between the teeth. Thus, by merely reversing the l-square upon the board the other longitudinal edge of the l-square will be brought into use as the reference line and this reference line will then be displaced onehalf of the distance between the teeth or one-quarter of an inch. Thus, the tooth spacing of one-half an inch which is uniform upon the l-square cross member and upon the edges of the board may be utilized by reversing the l-square to obtain spaces of the l-square which are one-quarter of an inch or one-half the distance between the teeth.

Although as illustrated in FIGS. 1 and 3, the guide blade 12 has cross members 56 secured to both its opposite ends for simultaneous engagement with the two opposite sets of tooth elements 20, it will be appreciated that in some instances it may be preferred to provide interlocking engagement at one end only of the blade.

Reference is made next to FIGS. 8-11 for an understanding of the construction and use of certain accessories and attachments which cooperate with the guide blade and its interlocking engagement with the board to obtain the location of the blade in proper orientation for forming various spacings of lines. For this purpose a pair of step spacers each indicated by the numeral 72 and of similar but reversed construction are provided for detachable mounting upon and sliding engagement along the guide blade 12. Each of these attachments comprises a block of a suitable material having a longitudinally extending channel 74 upon its underside of sufficient width to engage the top surface of the blade 52. The side walls of the channel 74 are stepped or shouldered as at 76 to provide bearing surfaces which rest upon the shoulder portion 62 recessed into the marginal edges of the blade 52, thereby leaving downwardly extending flanged portions or ribs as at 78 which embrace the outside edges of the blade 52. in this manner, each of the step spacers 72 is slidingly and guidingly mounted upon the blade 52 for sliding movement therealong. The outside vertical edges of the step spacers 72 are serrated or notched as at 80 to provide a plurality of parallel laterally spaced gauging surfaces 80. Each of these gauging surfaces is disposed at a fixed or definite distance from the corresponding edge of the blade 12, and indicia as at 82 are provided upon the face of the step spacer adjacent each of these gauging surfaces so as to indicate the magnitude of the displacement afforded thereby.

Cooperating with the step spacers 72 is a line and border rule indicated generally by the numeral 86 and shown in P10. 10. This rule has a flat planar bottom face as at 88 which slidingly engages the top surface 14 of the drawing board or of the paper sheet placed thereon. The top surface 90 of the rule is downwardly recessed as at 92 and 94 upon its opposite sides, each of which recessed portions are provided with a marginal edge as at 96 and 98 constituting a straight edge against which a drafting implement may be placed for guiding action therealong. One of the edges and surfaces 98, 94 is provided with notches or cutaway portions 100 therein of various configurations so that by moving a drafting pencil therealong, a correspondingly shaped wavy line may be formed. The other surface 92 is provided upon its top face with a series of recesses 102 so that by resting a drafting implement therealong, a broken or dotted line may be produced.

In the use of this implement, with the step spacers, as shown in FIG. 8, the spacers are positioned a sufficient distance apart to receive the ends of the rule 86 in appropriate corresponding recess surfaces 80. In this manner, by reference to the indicia 82, it will be seen that the ruler may be readily placed at a predetermined adjusted distance from the straight edge which is a fraction of the distance of spaces between two adjacent teeth of the interlocking means. In this manner, the one-half or one-quarter inch spacing of the interlocking means as previously described may be broken down into a very considerable number of small but accurate sub-divisions, thereby enabling great accuracy in the orientation of lines with respect to each other.

Referring next to the line guide of FIGS. 17-21, it will be observed that this instrument, indicated generally by the numeral 110, consists of a block of suitable material having a planar top surface as at 112 together with straight edge 114 at its opposite sides for sliding and guiding engagement against a straight edge such as that of the guide blade 52 or of the rule 86. However, the underside of the line spacer 110 has a flat coplanar bottom surface 116 parallel to its top surface 112 but which at its ends is beveled as at 118 to facilitate its sliding movement. Extending through this member are a series of guide apertures 120 through which a pen or pencil may be inserted. As shown best in FIGS. and 21, these apertures are staggered with respect to each other in two lines such that successive apertures will produce successive lines having a predetermined very small spacing therebetween. It will also be noted that the series of apertures are more closely adjacent to one edge of the body 110 then they are to the other so that in the position shown in FIG. 20, a series of lines 122 may be produced having a given spacing therebetween. However, when the body is turned around, after the first series of lines are formed, a second series of lines may be produced above the first series of lines as at 124. Also, the unequal spacing of the edges 114 from the apertures may include a factor of a fraction of the distance between two lines (such as, one-half) thereby making it possible to produce a much more closely spaced relation of the lines when the spacer 110 is turned around and properly repositioned with the apertures 120 in overlying relationship with the first series of lines. The sliding of the line spacer 110 may of course be guided by either the blade 52 or of the ruler 86.

Referring to FIG. 18 it will be noted that the undersurface 116 of the line spacer 110 is upwardly recessed to leave two flanges 128 along the marginal side edges thereof. These flanges reduce the friction of the sliding contact between the line spacer 110 and the surface over which it passes thereby facilitating sliding movement of the spacer during the drawing of a series of lines 122 and 124.

Reference is now made to a simplified and modified construction of drawing board, [square and interlocking connection therebetween as shown in FIGS. 12-16. In this form, the drawing board is designated generally by the numeral and a I-square by the numeral 142. The board is of identical construction previously described in connection with the board 10 except for the construction of the differing locking connecting means therefor. Consequently, the same numerals have been applied to corresponding parts for designating the various portions of the board and its attached structure. Similarly, the l-square 142 is identical with that previously described except for the construction of its cross member indicated by the numeral 144 and interlocking connection between this cross member and the board, which can be now described.

In this form of the invention, the top surface 14 of the board is recessed to provide marginal recessed surfaces 146. However, upon the vertical edges of these recessed surfaces there are provided vertical tooth surfaces as at 148. Correspondingly, the cross members 144 of the I-square are likewise provided with vertical tooth surfaces as at which cooperate with the surface 148 to effect an interlocking engagement therebetween. Inasmuch as interlocking engagement is effected between the vertical surfaces, it is possible to obtain a wedging action therebetween. Thus, as will be seen from FIG. 13, the teeth 148 have their outer edges inclined to the vertical as at 152. Similarly, the teeth 150 of the cross member 144 have their teeth I54 inclined as shown. The inclined surfaces 152 and 154 are so disposed that they produce a wedging action therebetween. Consequently, when the l-square is pressed downwardly upon the board, the tapers of the teeth of the cooperating surfaces will wedgingly engage and thus firmly secure the l-square to the board. This wedging action is such that it permits considerable wear to develop before sufficient loss of play developes or occurs to require readjustment. However, such readjustment is possible, as shown in FIG. 14, by virtue of the same elongated hole and fastener construction described in connection with the preceding embodiment of the invention and carrying the same reference numerals applied thereto.

As diagrammatically indicated in FIGS. 15 and 16, the tooth surface 150 on the cross member 144 are spaced a different distance from the opposite edges of the I-square 142 or at a distance of one-half the spacing of a tooth so as to obtain the same effect as that described in connection with the preceding embodiment. Thus, by reversing the l-square upon the board, a line can be drawn which is spaced intermediately of two consecutive lines drawn from consecutive teeth in the previous position of the l-square upon the board.

The same set of attachments and accessories described in connection with FIGS. 8-11 and FIGS.

17-21 with regard to the preceding embodiment of the adjustably positioned and locked upon the drawing board.

Reference is now made to FIG. 22, wherein is disclosed an alternative arrangement of the line spacing feature of the present inventive drafting system (compare with FIG. 8). In this figure and following figures, corresponding parts to those of the FIG. 8 embodiment are indicated with the same reference numerals for ease of understanding; the new elements being indicated by new reference numerals. Thus, broadly speaking, the drafting board 10 is provided with the I- square 12 which is fixedly positionable along the same and guided by recess surfaces 16. In lieu of using the separate ruler 86 and the two step spacers 72 as shown in FIG. 8, in accordance with the specific aspect of this embodiment, a rider rule 150 is provided which is adjustably attached to the I-square 12 and only one step spacer 72 is required.

Thus, the rider rule 150 comprises a transversely extending guide blade 151 and a pair of spaced support anns 152 which extend at a depending 45 degree angle thereto. As shown in FIG. 22 and 25, the underneath side of the arms 152 has a closed, recessed guide track 153 adapted to cooperate with an upstanding pin means in the form of a roller 154. As best shown in FIG. 25, the roller 154 may be mounted by a suitable vertical screw 155 passing finally through the cross member 56. As will be evident, when the blade 151 is to be adjusted along the drawing board 10, movement is effected in accordance with arrow 156 (see both FIGS. 22 and 23). This movement is at a 45 angle with respect to the board 10 and offers special advantages in terms of stability of the rider rule 150 at selected locations.

With the rider rule 150 movable along a 45 degree angle, there is always a component of force resisting movement along the board 10. In other words, at a 45 angle there is always a component of force resisting movement which is perpendicular to the I-square 12. As a result of this, the rider rule 150 is much easier to retain in a desired position against inadvertent movement during the drawing of the lines. Also, because of the angle the rider rule 150 may be more effectively moved through very small distances, i.e., a large movement in the direction of the arms 152 results in a smaller movement in the desired direction perpendicular to the I-square 12.

To roughly position the rider rule 150 with respect to the stationary I-square 12, a depending scale 160 may be attached to the guide blade 151. Reading increments 161 down the scale 160 readily shows the differences between lines drawn by the rider rule 150. Furthermore, a scale 162 may be provided along the I- square 12 with increments 163 which may be the same as the increments 161. Since the angle of the support arms 152 is at 45 degrees, as preferred, the same rough measurements may be taken horizontally along the scale 162 if desired. This is so as will be realized, since both the sine and the cosine of 45 are equal.

In addition to the scale 160, the guide blade 151 has a guide finger 165 depending downwardly toward the square 12 (see FIGS. 22 and 24). The guide finger 165 is provided with a free end 166 (see FIG. 26) which is adapted to cooperate with the single step spacer 72 at its guide surfaces 80.

In operation, assuming that the guide blade 151 of the rider rule 150 has been roughly positioned as desired by operation of the scale 160, the step spacer 72 is moved along the blade 52 of the I-square 12 from left to right (as viewed in FIG. 22) until one of the surfaces comes into engagement with the free end 166 of the guide finger in this case the number 3 surface. After firming up the engagement on the surface 80 and the side of the next higher step (by shifting the spacer 72 slightly to the right if necessary) the first line is drawn across the drawing surface, using the upper guide edge of the rider rule 150 in the usual manner. After this first line is drawn, the step spacer is shified to the left to bring the next lower (number four) stepped guide surface 80 into position slightly to the left of the end 166. The rider rule 150 is moved on a 45 degree down with the end 166 moving directly into firm engagement with the next surface 80 and the side of the juxtaposed step. This single movement of the spacer 72 and the rule 150 saves considerable time over systems where several moves of extra pieces are required before the next line is located. Thus, the second line may be drawn with a minimum of delay and is accurately spaced from the first line by the distance between the two stepped guide surfaces 80.

The selected distances between the surfaces 80 can be of any desired magnitude. For example, in the stepped spacer 72 shown in FIG. 22, an inch has been divided into ten equal parts so that the movement from one surface 80 to the adjacent surface equals one-tenth of an inch. Additional stepped spacers dividing an inch into 12 and 16 equal parts and others can of course be provided in accordance with the invention.

It will be realized that if additional spacing between adjacent lines being drawn on the drawing surface is desired and the additional spacing is divisible by whole numbers of the spacer divisions being used, the draftsman needs merely to skip one or more of the surfaces, as required, to obtain the desired results. If on the other hand, fractional increments of spacing is desired, in accordance with the present embodiment of the invention, notches 170 are provided along the edges of the finger 165. As shown in FIG. 26, the fractional increment provided in this particular case is onehalf the distance between adjacent guide surfaces 80. Thus, assuming that it is desired to draw two lines a half increment apart, a first position of the spacer 72 and the rider rule 150 is provided, as denoted by the dashdot outlines 72a and 150a of FIG. 26, wherein the number 2 guide surface 80 is positioned in the notch 170. After drawing the first line, the stepspacer 72 is shifted to the left to the full line position'of FIG. 26, and then the rider rule 150 is also shifted to its full line position thus bringing the end 166 into engagement with the number 3 guide surface 80. The second line can now be drawn immediately by the draftsman without further measurement and he is assured of having the exact spacing desired. The notch on the right hand side of the guide finger 165 may also be at the one-half increment, the same as the notch 170, so that it may be used with a similar step spacer 72, but one which has its guide surfaces 80 ascending rather than descending from left to right.

With reference back to FIG. 22 and FIG. 23, there is disclosed side guide which can be used with particular advantage in conjunction with the drafting system to determine the ends of each drafted line. The

side guide 175 is fabricated of spring material, such as a thin metal, and is formed with an inverted U-shaped recess 176. The recess 176 is formed with a discernible bow along the connecting portion of the U and the side portions of the U are spaced a distance substantially equal to the width of the blade 52 of the I-square 12. The side guide 175 can thus be snapped into position, as shown in FIG. 22, whereby it is held in position due to the frictional engagement between the edges of the blade 52 and the sides of the recess 176. The formation of the side guide 175 of thin material means that the rider rule 150 may be advantageously positioned on top of the same so that the drawing of the horizontal lines may proceed without any hindrance. Also, it will be noted that upon shifting the l-square 12 to another rough adjustment location determined by the teeth 20 along with recessed surfaces 16, the side guides 175 are carried therewith without change in positioning in readiness for performing their function of limiting the sidewise extent of the lines. The side guides 175 further serve as supports for the rider rule 150 so that upon lifting and shifting of the l-square 12, said rider rule 150 is advantageously also lifted and maintained in the desired relationship where otherwise it would like tip forward and fall off.

In summary, it will now be realized that the present applicant has provided a drafting board having several features particularly adapting the same for advantageous use in drawing a series of accurately spaced lines. The l-square is maintained in locked position at two spaced points by the engaging teeth of recessed surfaces 16. The step spacers 72 perform their function so that no tedious measurement between lines is required. In an alternative embodiment of the step spacer feature, a rider rule 150 is provided which allows the draftsman to move quickly and with minimum chance of error by manipulating only a single step spacer 72 that cooperates with the guide finger 165 on said rule 50. The side guides 175 extending under the rider rule 150 serve to delineate the ends of the lines and secondarily to retain the rule 50 in the desirable supported relationship on the I-sq uare 12 at all times.

What is claimed as new is as follows:

I. A draftsmans apparatus comprising in combination a drawing board together with a guide blade movable thereacross, interlocking means on said guide blade and board releasably connecting them together in adjustable, selected parallel positions of predetermined spacing, said interlocking means comprising cooperating series of locking elements on said board and blade, the elements of each series being spaced by a predetermined distance whereby to orient said blade upon said board at selected locations for drawing lines spaced from each other in accordance with said predetermined distances, said board has upon its top surface marginal depressed surfaces, said board locking elements being disposed upon and projecting up from said depressed surfaces, said locking elements being engageable with selected elements of said depressed surfaces, the locking elements of said board and blade each lying below said board top surface.

2. The combination of claim 1 wherein said board is of translucent material and has a recess in its bottom surface, legs hinged and foldable into said recess for supporting said board in an inclined position to the horizontal, latch means releasably retaining said legs in folded position in said recess.

3. The combination of claim 1 wherein said guide blade has a cross member secured at each end thereof, said blade locking elements being disposed on said cross-member, fastening means adjustably securing said cross-member to said blade.

4. A draftsman's apparatus comprising in combination a drawing board together with a guide blade movable thereacross, interlocking means on said guide blade and board releasably connecting them together in adjustable, selected parallel positions of predetermined spacing, said interlocking means comprising cooperating series of locking elements on said board and blade, the elements of each series being spaced by a predetermined distance whereby to orient said blade upon said board at selected locations for drawing lines spaced from each other in accordance with said predetermined distances, step spacer slides detachably and slidably mounted on said blade for sliding movement therealong, said slides having complementary pairs of gauge surfaces disclosed at successively varying distances from the sides of said blade, a ruler engaged in selected pairs of complementary gauge surfaces thereby to adjustably vary the distance of the ruler edge relative to that of said blade, said blade having a planar top surface with marginal depressed surfaces, said step spacers being each a channel on its bottom surface slidably receiving said blade therein, said channel having recessed surfaces engaging said blade depressed surfaces.

5. A draftsmans apparatus comprising in combination a drawing board together with a guide blade movable thereacross, interlocking means on said guide blade and board releasably connecting them together in adjustable, selected parallel positions of predetermined spacing, said interlocking means comprising cooperating series of locking elements on said board and blade, the elements of each series being spaced by a predetermined distance whereby to orient said blade upon said board at selected locations for drawing lines spaced from each other in accordance with said predetermined distances, step spacer slides detachably and slidably mounted on said blade for sliding movement therealong, said slides having complementary pairs of gauge surfaces disposed at successively varying distances from the sides of said blade, a ruler engaged in selected pairs of complementary gauge surfaces whereby to adjustably vary the distance of the ruler edge relative to that of said blade, said ruler having vertical guide edges at its opposite sides, one of said guide edges having cut out portions for causing a scriber moving therealong to produce a wavy or broken line, the other edge of the ruler having horizontal depressions for causing a scriber to produce a broken or dash line.

6. In a drafting apparatus, at least one spacer movably engaged with a straight edge and including a plurality of stepped surfaces parallel to but spaced from the straight edge, and a parallel rule engaging a selective one of the stepped surfaces and including a second straight edge parallel to spaced from the straight edge engaged by the spacer, and means for holding said rule steady in engagement with said one surface to allow accurate parallel line drafting therewith.

7. The structure as defined in claim 6 wherein said holding means includes an additional spacer having corresponding stepped surfaces, said rule extending between two of said surfaces one on each of said spacers.

8. A drafting apparatus comprising in combination a drawing board together with a guide square movable therealong, a rider rule attached to said guide square, and means for mounting said rule for adjustable movement on said square along said board, whereby lines at selected increments may be drawn without movement of said guide means, said adjustable mounting means comprises a support arm at each end of the rule, a guide track on the underneath side of each of said arms, said guide track closed from the top to form downwardly facing cavities, rollers on said guide square to cooperate with said cavities for smoothly guiding said rider rule, the axis of rotation of said rollers being perpendicular to said guide square.

9. The drafting apparatus of claim 8 wherein said tracks extend at equal angles of approximately 45 to said guide square to provide a station keeping force perpendicular to said guide square.

10. The drafting apparatus of claim 8 wherein is provided a scale fixed perpendicularly on said rider rule and movable diagonally with respect to said guide square to selectively position said rule.

ll. A drafting apparatus comprising in combination a drawing board together with a guide square movable thercalong, a rider rule attached to said guide square, and means for mounting said rule for adjustable movement on said square along said board, whereby lines at selected increments may be drawn without movement of said guide means, a step spacer slide mounted on said guide square, said slide having guide surfaces disposed at successively varying distances from the edge of said guide square, and a guide finger mounted on said rule, the free end of said finger being adapted for cooperation with said surfaces whereby to adjustably vary the rule corresponding to said surfaces.

12. The drafting apparatus of claim 11 wherein said the free end of said finger has at least one notch adjacent an edge thereof, said notch being spaced from said end by a fraction of the distance between said surfaces whereby corresponding increment of spacing between the lines can be gained.

13. A drafting apparatus comprising in combination a drawing board together with a guide square movable therealong, a rider rule attached to said guide square, and means for mounting said rule for adjustable movement on said square along said board, whereby lines at selected increments may be drawn without movement of said guide means, a side guide is provided on said guide square, said side guide being sufficiently thin to extend beneath said rider rule to support the same.

14. The drafting apparatus of claim 13 wherein said side guide is formed of spring material, a U-shaped offset being formed in said guide substantially equal to the width of said guide square the connecting portion of said offset being bowed to cause said offset to snap onto said guide square for locking said side guide in position.

15. A drafting apparatus comprising in combination a drawing board together with a guide square movable the ealong, a rider rule attaghe i t sai ui s uare, an mean for mounting sai rue ora sta e ovement on said square along said board, whereby lines at selected increments may be drawn without movement of said guide means, said board and said guide square have sets of cooperating locking elements at each end thereof for simultaneously fixedly securing said guide element to said board at both ends of the guide element, a pair of side guides mounted on said guide square and being sufficiently thin to extend under said rider rule, whereby said lines may be made a predetermined length.

swea s UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,688 ,409 Dated Sept m er 5. 1972 Murray K. Rogers, deceased, late of Somerset, Ky.; Inventor(s) by May B. Rogers, Executrix It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

The inventor's name is corrected from "Robers, deceased" and "Murray K. Robers" to Rogers, deceased and -Murray K. Rogerson the title page.

Signed and sealed this lst day of May 1973.

(SEAL) fattest:

EDWARD 1'. FLZTUHLGR, JR. ROBERT GOTTSCHALK lttestiflg Officer Commissioner of Patents CRM PO-iOSO [10-69) USCOMM-DC 60376-5 69 Q u 5 GOVERNMENT PRINTING OFFKLE 1969 o-aee-asn 

1. A draftsman''s apparatus comprising in combination a drawing board together with a guide blade movable thereacross, interlocking means on said guide blade and board releasably connecting them together in adjustable, selected parallel positions of predetermined spacing, said interlocking means comprising cooperating series of locking elements on said board and blade, the elements of each series being spaced by a predetermined distance whereby to orient said blade upon said board at selected locations for drawing lines spaced from each other in accordance with said predetermined distances, said board has upon its top surface marginal depressed surfaces, said board locking elements being disposed upon and projecting up from said depressed surfaces, said locking elements being engageable with selected elements of said depressed surfaces, the locking elements of said board and blade each lying below said board top surface.
 2. The combination of claim 1 wherein said board is of translucent material and has a recess in its bottom surface, legs hinged and foldable into said recess for supporting said board in an inclined position to the horizontal, latch means releasably retaining said legs in folded position in said recess.
 3. The combination of claim 1 wherein said guide blade has a cross member secured at each end thereof, said blade locking elements being disposed on said cross-member, fastening means adjustably securing said cross-member to said blade.
 4. A draftsman''s apparatus comprising in combination a drawing board together with a guide blade movable thereacross, interlocking means on said guide blade and board releasably connecting them together in adjustable, selected parallel positions of predetermined spacing, said interlocking means comprising cooperating series of locking elements on said board and blade, the elements of each series being spaced by a predetermined distance whereby to orient said blade upon said board at selected locations for drawing lines spaced from each other in accordance with said predetermined distances, step spacer slides detachably and slidably mounted on said blade for sliding movement therealong, said slides having complementary pairs of gauge surfaces disclosed at successively varyiNg distances from the sides of said blade, a ruler engaged in selected pairs of complementary gauge surfaces thereby to adjustably vary the distance of the ruler edge relative to that of said blade, said blade having a planar top surface with marginal depressed surfaces, said step spacers being each a channel on its bottom surface slidably receiving said blade therein, said channel having recessed surfaces engaging said blade depressed surfaces.
 5. A draftsman''s apparatus comprising in combination a drawing board together with a guide blade movable thereacross, interlocking means on said guide blade and board releasably connecting them together in adjustable, selected parallel positions of predetermined spacing, said interlocking means comprising cooperating series of locking elements on said board and blade, the elements of each series being spaced by a predetermined distance whereby to orient said blade upon said board at selected locations for drawing lines spaced from each other in accordance with said predetermined distances, step spacer slides detachably and slidably mounted on said blade for sliding movement therealong, said slides having complementary pairs of gauge surfaces disposed at successively varying distances from the sides of said blade, a ruler engaged in selected pairs of complementary gauge surfaces whereby to adjustably vary the distance of the ruler edge relative to that of said blade, said ruler having vertical guide edges at its opposite sides, one of said guide edges having cut out portions for causing a scriber moving therealong to produce a wavy or broken line, the other edge of the ruler having horizontal depressions for causing a scriber to produce a broken or dash line.
 6. In a drafting apparatus, at least one spacer movably engaged with a straight edge and including a plurality of stepped surfaces parallel to but spaced from the straight edge, and a parallel rule engaging a selective one of the stepped surfaces and including a second straight edge parallel to spaced from the straight edge engaged by the spacer, and means for holding said rule steady in engagement with said one surface to allow accurate parallel line drafting therewith.
 7. The structure as defined in claim 6 wherein said holding means includes an additional spacer having corresponding stepped surfaces, said rule extending between two of said surfaces one on each of said spacers.
 8. A drafting apparatus comprising in combination a drawing board together with a guide square movable therealong, a rider rule attached to said guide square, and means for mounting said rule for adjustable movement on said square along said board, whereby lines at selected increments may be drawn without movement of said guide means, said adjustable mounting means comprises a support arm at each end of the rule, a guide track on the underneath side of each of said arms, said guide track closed from the top to form downwardly facing cavities, rollers on said guide square to cooperate with said cavities for smoothly guiding said rider rule, the axis of rotation of said rollers being perpendicular to said guide square.
 9. The drafting apparatus of claim 8 wherein said tracks extend at equal angles of approximately 45* to said guide square to provide a station keeping force perpendicular to said guide square.
 10. The drafting apparatus of claim 8 wherein is provided a scale fixed perpendicularly on said rider rule and movable diagonally with respect to said guide square to selectively position said rule.
 11. A drafting apparatus comprising in combination a drawing board together with a guide square movable therealong, a rider rule attached to said guide square, and means for mounting said rule for adjustable movement on said square along said board, whereby lines at selected increments may be drawn without movement of said guide means, a step spacer slide mounted on said guide square, said slide having guide surfaces disposed at successively varying distances from thE edge of said guide square, and a guide finger mounted on said rule, the free end of said finger being adapted for cooperation with said surfaces whereby to adjustably vary the rule corresponding to said surfaces.
 12. The drafting apparatus of claim 11 wherein said the free end of said finger has at least one notch adjacent an edge thereof, said notch being spaced from said end by a fraction of the distance between said surfaces whereby corresponding increment of spacing between the lines can be gained.
 13. A drafting apparatus comprising in combination a drawing board together with a guide square movable therealong, a rider rule attached to said guide square, and means for mounting said rule for adjustable movement on said square along said board, whereby lines at selected increments may be drawn without movement of said guide means, a side guide is provided on said guide square, said side guide being sufficiently thin to extend beneath said rider rule to support the same.
 14. The drafting apparatus of claim 13 wherein said side guide is formed of spring material, a U-shaped offset being formed in said guide substantially equal to the width of said guide square the connecting portion of said offset being bowed to cause said offset to snap onto said guide square for locking said side guide in position.
 15. A drafting apparatus comprising in combination a drawing board together with a guide square movable therealong, a rider rule attached to said guide square, and means for mounting said rule for adjustable movement on said square along said board, whereby lines at selected increments may be drawn without movement of said guide means, said board and said guide square have sets of cooperating locking elements at each end thereof for simultaneously fixedly securing said guide element to said board at both ends of the guide element, a pair of side guides mounted on said guide square and being sufficiently thin to extend under said rider rule, whereby said lines may be made a predetermined length. 